Table saws of the type which have a circular cutting blade are well known and have been used by tradesmen and woodworkers for decades. Because they have a generally flat surface, large and small boards as well as plywood sheets can be cut to the appropriate size by typically setting a fence at the appropriate position to perform a cut along a desired line which is done by pushing the board or sheet across the tabletop and through the blade. Typically, the fence is adjustable by sliding along an elongated rail anchored at opposite ends of the table saw top, with the fence having a clamping mechanism to lock the fence once it has been placed in the desired position. Most users, when they know the width of the desired board will use a tape measure or other measure to position the fence to obtain the desired width by measuring between the edge of the blade to the fence. After the fence is in position, it is locked in place and users typically remeasure the distance to make sure that they have the fence in the correct position.
While the manual measurement and setting of the position of the fence is the manner in which the fence has been positioned by most users over the years, in some instances it is highly desirable to have very accurate measurements which may be difficult depending upon the type of measuring device is being used. Most tape measures, for example, do not have accurate measurements beyond a 1/32 of an inch or less. Also, if the fence is moved during other types of cuts, it is not possible to reset the fence at exactly the same position that was used for a prior cut without going through the complete exercise again. If the user does not remember the prior cut distance, then additional measurements of a work-piece may be necessary in order to obtain the distance which must then be used to correctly position the fence.